A fallacy of whataboutism (or "whataboutery") is either a tu quoque or a red herring fallacy that is introduced by the phrase, "What about....?"

This is a rhetorical question meant to shift the topic of debate. It is therefore a fallacy of relevance, as it switches attention away from the main topic.

It is important to be aware that the words "what about" are not always indicative of this fallacy -- see note below.

Here is a tu quoque example:

Jenny: "You eat too much ice cream."

Lenny: "What about all the candy bars you eat? Leave me alone, hypocrite!"

Even if Jenny is being hypocritical, it doesn't affect whether her assertion is correct about Lenny's ice cream habit.

Here is a red herring example:

Lenny: "We should do something about all the jay-walking downtown. There was another accident this week. We need to get more police patrolling those intersections."

Jenny: "What about all the shoplifting downtown? Let's have the police fix that first!"

Even if Jenny is correct about shoplifting being a problem in their town, it does not mean Lenny's suggestion lacks merit.

​Note: Not every occurrence of the phrase "What about..." is an instance of this fallacy. When these words introduce a tu quoque or a red herring, then it is fallacious. In other instances, it can be appropriate to say "but what about" in order to correct a sweeping generalization or other defect in someone's previous statement.

Conversely, the exact phrase "what about" is not required in this fallacy. In the example above, if Jenny had said, "But think about the shoplifting...", it would still be an example of whataboutism.

​ ​